The DeSoto Firesweep, particularly the 1958 facelifted 4-door sedan equipped with the PowerPack 5.7 V8 engine and PowerFlite automatic transmission, represents a pivotal, though ultimately short-lived, moment in the American automotive landscape. Produced from 1957 to 1958, the Firesweep was positioned as DeSoto’s full-size offering, aiming to bridge the gap between the more affordable DeSotos and the luxury-oriented Chrysler models. This specific configuration, boasting 295 horsepower, was a mid-range offering within the Firesweep lineup, providing a balance of performance and convenience for the American family.
Technical Specifications
| Brand | DeSoto |
| Model | Firesweep |
| Generation | Firesweep I 4-Door Sedan (facelift 1958) |
| Type (Engine) | PowerPack 5.7 V8 (295 Hp) PowerFlite |
| Start of production | 1957 |
| End of production | 1958 |
| Powertrain Architecture | Internal Combustion engine |
| Body type | Sedan |
| Seats | 6 |
| Doors | 4 |
| Fuel Type | Petrol (Gasoline) |
| Power | 295 Hp @ 4600 rpm |
| Power per litre | 51.4 Hp/l |
| Torque | 522 Nm @ 2800 rpm / 385.01 lb.-ft. @ 2800 rpm |
| Engine displacement | 5735 cm3 / 349.97 cu. in. |
| Number of cylinders | 8 |
| Engine configuration | V-engine |
| Cylinder Bore | 103.12 mm / 4.06 in. |
| Piston Stroke | 85.85 mm / 3.38 in. |
| Compression ratio | 10:1 |
| Number of valves per cylinder | 2 |
| Fuel injection system | Carburettor |
| Engine aspiration | Naturally aspirated engine |
| Valvetrain | OHV |
| Engine oil capacity | 3.8 l / 4.02 US qt | 3.34 UK qt |
| Coolant | 16.1 l / 17.01 US qt | 14.17 UK qt |
| Fuel tank capacity | 87 l / 22.98 US gal | 19.14 UK gal |
| Length | 5499 mm / 216.5 in. |
| Width | 1989 mm / 78.31 in. |
| Height | 1443 mm / 56.81 in. |
| Wheelbase | 3099 mm / 122.01 in. |
| Front track | 1547 mm / 60.91 in. |
| Rear track | 1516 mm / 59.69 in. |
| Front overhang | 940 mm / 37.01 in. |
| Rear overhang | 1461 mm / 57.52 in. |
| Ride height (ground clearance) | 142 mm / 5.59 in. |
| Minimum turning circle | 14.2 m / 46.59 ft. |
| Approach angle | 16.5° |
| Departure angle | 11.4° |
| Ramp-over angle | 10.5° |
| Drivetrain Architecture | Rear wheel drive |
| Drive wheel | Rear wheel drive |
| Number of gears and type of gearbox | 2 gears, automatic transmission PowerFlite |
| Front suspension | Independent coil spring |
| Rear suspension | Leaf spring |
| Front brakes | Drum, 279 mm |
| Rear brakes | Drum, 279 mm |
| Steering type | Worm-reduction unit |
Powertrain & Engine Architecture
The heart of this Firesweep variant was the DeSoto PowerPack 5.7-liter (349.97 cubic inch) V8 engine. This engine, designated with various codes depending on specific calibration, was a robust OHV (Overhead Valve) design. It featured a cast iron block and cylinder heads, and utilized a carburetor for fuel delivery. The 10:1 compression ratio contributed to the engine’s respectable power output. The PowerFlite automatic transmission, a two-speed unit, was specifically designed to handle the V8’s torque. While not as sophisticated as some contemporary automatics, the PowerFlite was known for its durability and relatively smooth operation. The transmission’s gear ratios were optimized for cruising, prioritizing comfortable highway driving over rapid acceleration.
Driving Characteristics
The 1958 Firesweep with the 295 hp V8 and PowerFlite transmission offered a driving experience typical of large American sedans of the era. Acceleration was adequate, but not particularly brisk, especially when compared to models equipped with higher-output engines or manual transmissions. The PowerFlite’s two-speed configuration meant that gear changes were noticeable, and the engine could feel strained during hard acceleration. However, the car excelled at relaxed highway cruising, providing a comfortable and stable ride. The suspension, featuring independent coil springs in the front and leaf springs in the rear, absorbed bumps reasonably well, though it wasn’t particularly sporty in handling. The steering, utilizing a worm-reduction unit, was known for being somewhat vague and requiring considerable effort at low speeds.
Equipment & Trim Levels
The 1958 Firesweep, in its base configuration with the 5.7L V8 and PowerFlite, came standard with features considered essential for the time. These included a spacious interior upholstered in cloth and vinyl, a full-width bench seat, and a basic instrument panel. Power steering and power brakes were often optional extras. The Firesweep offered a range of optional equipment, including air conditioning, a radio, whitewall tires, and two-tone paint schemes. Interior trim levels could be upgraded with more luxurious materials and finishes. The overall aesthetic was characterized by the flamboyant styling of the late 1950s, featuring generous chrome accents and sweeping tailfins.
Chassis & Braking
The Firesweep rode on a traditional body-on-frame chassis. The front suspension utilized independent coil springs, providing a degree of ride comfort. The rear suspension employed leaf springs, a cost-effective and durable design. Braking was accomplished via drum brakes on all four wheels, measuring 279mm in diameter. While adequate for the car’s weight and performance, the drum brakes lacked the stopping power and fade resistance of disc brakes, which were still relatively uncommon at the time. Steering was handled by a worm-reduction unit, which provided a simple and reliable, but somewhat imprecise, steering feel.
Market Reception & Comparison
The 1958 Firesweep, while visually striking, faced stiff competition from other American automakers. Critics generally praised the car’s styling and spacious interior, but noted its somewhat lackluster performance compared to some rivals. The PowerFlite transmission, while durable, was seen as a bit dated compared to the more modern automatics offered by Ford and General Motors. The 295 hp V8 offered a good balance of power and fuel economy, but the higher-output engines available in other DeSoto models and competing brands were more appealing to performance-minded buyers. Compared to the Firesweep’s siblings, such as those equipped with the more powerful 325 hp V8, this variant represented an entry-level option, appealing to buyers prioritizing comfort and affordability over outright performance.
Legacy
The DeSoto Firesweep, and the DeSoto brand as a whole, was discontinued after 1961 due to declining sales and increasing competition. The 1958 model, while not a commercial success, remains a popular choice among classic car enthusiasts. The PowerPack 5.7 V8 engine, when properly maintained, proved to be a durable and reliable powerplant. However, finding parts for these older engines can be challenging today. The PowerFlite transmission, while robust, is susceptible to wear and tear over time. Today, the 1958 Firesweep represents a unique and stylish piece of American automotive history, offering a glimpse into the design and engineering philosophies of the late 1950s. Well-preserved examples command a moderate price in the collector car market, appealing to those seeking a classic American cruiser.
